INSECTA : DIPTERA 



335 



to ten days the cocoon (larval skin) is broken at one end, and 

 the fly emerges. 



There are two broods in the year ; the flies may emerge in 

 the early spring or in the late summer. 



Family 3 : Stratiomyidae (the Chamelbon-flibs) 



The family of the Stratiomyidae is a large and varied one. 

 The flies are usually big and rather bee-like, and from the 

 hind margin of the thorax there pro- 

 ject two very small spines which 

 give the name of "Stratiomys" or 

 " Armed-fly " to the typical genus. 

 The wings are rather small rela- 

 tively, and have a simple but well- 

 marked nervature. 



The Common Chameleon-fly 



(Stratiomys chamaeleon). 



This is a strong active fly, decidedly 

 bee-like in appearance. The thorax 

 is thick and muscular ; tlie broad 



FlQ. 256.— The Chameleou- 

 fly (Stratiomys chainae- 

 lean). 



A, Side view ; B, dorsal view, 



and rather flat abdomen is 

 black with yellow mark- 

 ings, and the wings do not 

 reach beyond it. It may 

 often be seen feeding on 

 the nectar of flowers, or 

 near the water preparing 

 to lay its eggs, for in this 

 case again the larvae are 

 aquatic. It has a rapid 

 short flight, and very often 

 flies ofi" only to return to 

 the same spot, The eggs 



FlQ. 257. — Stratiomys chamaeleon. 



On the left, leaf with eggs ; on the right, 

 two larvae, one resting at the surface 

 and one swimming downwards. 



